The present invention relates to a mixing apparatus having a function for performing signal processing operations on a cue signal (i.e., audio signal output from a CUE bus) for auditorily monitoring a signal of a selected section of the mixing apparatus on the basis of cue operation, and a method for setting ON or OFF of the individual signal processing operations in the mixing apparatus.
As one form of audio signal processing apparatus, there have heretofore been known mixing apparatus for use in concerts, events, gatherings, theatrical performances, etc., which are constructed to mix audio signals, output from a multiplicity of microphones, electric and electronic musical instruments, etc. after adjusting levels and frequency characteristics of the audio signals and then output the mixed audio signals to a power amplifier. A human operator, operating such a mixing apparatus, operates various panel controls of the mixing apparatus to adjust volumes and colors of audio signals of musical instrument tones and singing voices into states that appear to most suitably express a performance. The mixing apparatus includes a plurality of input channels, mixing buses for mixing sound signals (audio signals) supplied from the input channels, and output channels for outputting mixed sound signals. Each of the input channels controls frequency characteristics, mixing level, etc. of a sound signal input thereto and then outputs the thus-controlled sound signal to the individual mixing buses, and each of the mixing buses mixes the sound signals input from the input channels and outputs the mixed sound signal to a corresponding one of the output channels. Output signals from the output channels are amplified and audibly output through speakers etc.
Such mixing apparatus are equipped with a CUE function section for auditioning or auditorily monitoring a signal of a given input channel or output channel on the basis of cue operation without changing mixing (adjustment) states in the mixing apparatus. With the cue function, a signal of a selected input channel or output channel is supplied to a CUE bus in response to turning-on of a CUE switch of a channel strip controlling the input channel or output channel, so that an audio signal output from the CUE bus (hereinafter referred to as “CUE signal”) is output to a human operator through headphones, monitoring speaker or the like. In this case, a sound heard from a main speaker takes on a propagation delay at the position of the human operator of the mixing apparatus, and thus, a delay portion for delaying the cue signal is provided in the cue function section in order to absorb a time difference between the sound heard from the main speaker and the cue signal auditorily monitored by the human operator on the basis of cue operation.
Conventionally, even where a signal of an input channel is cued or monitored, the delay portion in the cue function section delays the cue signal. But, the signal of the input channel is a pre-mixing signal (i.e., signal before being subjected to mixing processing) and only part of a sound signal output from the main speaker, and thus, when cuing or monitoring the signal of the input channel, there is no need to conform the phase of the signal of the input channel to the phase of the sound signal output from the main speaker. Rather, when the input channel is to be cued, it is desired to monitor a non-delayed real-time cue signal; however, none of the conventionally-known mixing apparatus can monitor such a real-time cue signal because the signal of the input channel to be cued is delayed by the cue function section as noted above. Thus, it has been proposed that, once cuing is instructed, a determination be made as to whether the channel to be cued is an input channel or an output channel, and a delay operation be bypassed if the channel to be cued is an input channel.
Further, each of the output channels includes an equalizer portion that not only adjusts frequency balance at an audience's listening position but also prevents unwanted howling caused by a microphone within a venue. Further, in a monitor room, which has a smaller area than the venue, a blurred sound would be generated with low-frequency components of the sound confined within the monitor room. Thus, the cue function section uses an equalizer to reduce a boomy region so as to adjust a sound image to be clearer, and then outputs the thus-adjusted sound to the monitor room. However, the equalizer in the cue function section is constantly kept operative, and thus, when a signal of a given output channel is to be auditorily monitored on the basis of cue operation, signal processing is performed on a cue signal by both the equalizer inserted in the given output channel and the equalizer inserted in the cue channel; in this case, it is not possible to auditorily check as-is the sound of the given output channel. Therefore, it is presently proposed that, once cuing is instructed (i.e., a cue instruction is issued), a determination be made as to whether the channel to be cued is an input channel or an output channel, and a delay operation be bypassed if the channel to be cued is an output channel.
With the development of digital mixer techniques in recent years, it has become possible to diversify signal processing operations to be performed on a cue signal. For example, the inventors of the present invention propose that a CUE signal processing section include an insert portion in addition to delay and equalizer portions and that signal processing operations be performed on a signal, input to a CUE signal processing section, with an effecter etc. inserted. However, if the signal processing operations are diversified like this, operation for setting signal processing to be performed in accordance with a category of the cue signal would become very complicated, and thus, the conventionally-known mixing apparatus cannot appropriately deal with the diversification of the signal processing.